Door seal for automobile and molding method and device therefor

ABSTRACT

A method and apparatus for molding a door seal, such as for an automobile. The apparatus is provided with a first extrusion passage for extruding a molding material into a hollow portion of the door seal. A second extrusion passage is provided for extruding molding material into a bridge which spans across the hollow portion of the door seal. A molding material discharge member, such as a pipe, is movably inserted into the molding die and can be moved between open and closed positions relative to a molding material supply passage for permitting material to be intermittently extruded through the second passage, whereas material is substantially continuously extruded through the first passage, thereby permitting the bridge to be molded to the hollow portion at selected locations therealong.

FIELD OF THE INVENTION

The present invention relates to a door seal adapted to be mounted on aninner periphery of a door opening of a body of an automobile, so as toseal between the inner periphery of the door opening and an outerperiphery of a door upon closing the door. The present invention alsorelates to a molding method and device for such a door seal.

BACKGROUND OF THE INVENTION

A hollow door seal for an automobile (hereinafter referred to simply asa door seal) includes a part provided with a bridge in a hollow portionand a part provided with no bridge in the hollow portion, depending onthe mounting position of the door seal.

In an automobile of a hard-top type mounting a door mirror thereon, forexample, the door seal is formed by connecting three kinds of door sealparts as shown in FIG. 13. That is, three kinds of door seal parts S'₁,S'₂ and S'₃ having different sectional shapes are independently formed.The door seal part S'₁ and the door seal part S'₂, both constituting astraight front side portion of the door seal where the door mirror islocated, are bonded together at a connecting portion A. Further, thedoor seal part S'₂ constituting the front side portion and the door sealpart S'₂ constituting an upper side portion of the door seal arecorner-molded and connected together at a connecting portion B. The doorseal part S'₂ constituting the upper side portion and the door seal partS'₃ constituting a rear side portion of the door seal are alsocorner-molded and connected together at a connecting portion B'.

The door seal part S'₁ to be mounted at a position where the door mirroris located has no bridge in the hollow portion, so as to reduce the sealreaction generated due to deformation when the door mirror contacts thedoor seal part S'₁, and thereby ensuring ready fitting of the doormirror with the door seal part S'₁. In contrast, the door seal part S'₂mounted at a position where a window glass of the door is located has abridge in the hollow portion, so as to generate a large seal reactionand thereby ensure a high sealability when the window glass comes intocontact with the door seal part S'₂. Further, the connecting portion Bat the front corner of the door seal is formed of a seal member havingthe same structure as that of the door seal part S'₁. That is, theconnecting portion B has no bridge in the hollow portion. Further, lowerends F of the door seal parts S'₁ and S'₃ are end-molded.

As mentioned above, the conventional door seal for an automobilemounting a door mirror thereon employs three kinds of door seal parts,and requires corner-molding at two positions and straight-bonding at oneposition. Accordingly, the number of manufacturing steps in the moldingoperation is increased, and the connecting portions are visiblyperceived to deteriorate the appearance.

It is accordingly an object of the present invention to eliminate theconnecting portions by integrally forming a first door seal portionhaving no bridge in the hollow portion and a second door seal portionhaving a bridge in the hollow portion by continuous molding.

According to the present invention for achieving the above object, thereis provided a molding method for a door seal for an automobile,comprising the steps of separately forming a first extrusion passage forextruding a molding material into a hollow portion of said door seal anda second extrusion passage for extruding a molding material into abridge in the hollow portion of said door seal in an extrusion openingof a molding die with use of a core, axially moving a molding materialdischarge pipe inserted into said molding die, and repeatedly closingand opening a molding material supply passage communicated with saidsecond extrusion passage so as to intermittently extrude the moldingmaterial from said second extrusion passage.

The material to be molded into the body portion of the door seal iscontinuously extruded. However, the material to be molded into thebridge in the hollow portion of the door seal is intermittently extrudedfrom the second extrusion passage by repeating the closing and openingof the molding material supply passage as communicated with the secondextrusion passage by axial movement of the molding material dischargepipe. Accordingly, the first door seal portion having no bridge in thehollow portion and the second door seal portion having the bridge in thehollow portion can be continuously molded.

As a result, the connecting portion between the first and second doorseal portions can be eliminated to thereby improve the appearance.Further, the number of manufacturing steps for the connection betweenthe seal parts necessary in the prior art method can be eliminated tothereby improve the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 12 are illustrations for explaining the present invention.

FIG. 1 is a front elevational view of a molding device to be used inmolding the first hollow molding part E₁ ;

FIG. 2 is a cross section taken along the line 2--2 in FIG. 1;

FIG. 3 is a view similar to FIG. 2, and shows a device for molding thesecond hollow molding part E₂ ;

FIG. 4 is a perspective view of the molding material discharge pipe P;

FIG. 5(a) is a front elevational view of the first die D₁ ;

FIG. 5(b) is a cross section taken along the line 5--5 in FIG. 5(a);

FIG. 6(a) is a front elevational view of the second die D₂ ;

FIG. 6(b) is a cross section taken along the line 6--6 in FIG. 6(a);

FIG. 7(a) is a front elevational view of the third die D₃ ;

FIG. 7(b) is a cross section taken along the line 7--7 in FIG. 7(a);

FIG. 8 is a perspective view of the hollow molding E formed according tothe present invention;

FIG. 9 is a side view of the door seal S formed according to the presentinvention;

FIG. 10 is a cross section taken along the line 10--10 in FIG. 9;

FIG. 11 is a cross section taken along the line 11--11 in FIG. 9;

FIG. 12 is a sectional view of the first door seal portion S₁ having nobridges 14 as shown by a dashed line; and

FIG. 13 is a side view of the door seal formed by the conventionalmolding method.

DETAILED DESCRIPTION

There will first be described the molding method according to thepresent invention with reference to FIGS. 1 to 7.

A molding die D is constructed by overlapping first, second and thirddie parts D₁, D₂ and D₃. As shown in FIGS. 5(a) and 5(b), the first diepart D₁ is formed substantially as a cylindrical-shaped plate or diskprovided at its central portion with a first core C₁ having asemicircular cross section and projecting outwardly from a front surfaceof the die part D₁. The first die part D₁ is further formed on its frontsurface with a molding material supply passage or groove V₁ extendingfrom an outer circumference of the front surface to the first core C₁.The supply passage V₁, intermediate the ends thereof, is formed with arecess 1 for receiving a base end of a molding material discharge pipe Pwhich will be hereinafter described. The recess 1 is formedsubstantially as a blind cylindrical bore having an axial depth greaterthan that of the passage V₁. The supply passage V₁ serves as a passagefor supplying a molding material to be molded into a bridge 4 in ahollow portion 3 of a hollow molding E.

As shown in FIGS. 6(a) and 6(b), the second die part D₂ is also formedsubstantially as a cylindrical-shaped plate or disk provided at itscentral portion with a second core C₂ having a semicircular crosssection and projecting outwardly from a front surface of the die partD₂. An extrusion opening 5 having a semicircular cross section is formedaxially through the second die part D₂ at a position adjacent to thesecond core C₂. The second die part D₂ is further formed on its frontsurface with a molding material supply passage or groove V₂ extendingfrom an outer circumference of the front surface to the extrusionopening 5. The first core C₁ of the first die part D₁ is symmetricalwith the second core C₂ of the second die part D₂ with respect to theaxially aligned centers of the die parts D₁ and D₂ after they areoverlapped. The supply passage V₂ serves as a passage for supplying amolding material to be molded into an upper half of a body portion 2 ofthe hollow molding E.

As shown in FIGS. 7(a) and 7(b), the third die part D₃ is formed as acylindrical-shaped plate or disk provided at its central portion with anextrusion opening 6 having a circular cross section and extendingcoaxially therethrough. The third die part D₃ is further formed on itsrear surface with a molding material supply passage or groove V₃extending from an outer circumference of the rear surface to theextrusion opening 6. The supply passage V₃ serves as a passage forsupplying a molding material to be molded into a lower half of the bodyportion 2 of the hollow molding E.

Both the second and third die parts D₂ and D₃ are formed with alignedpipe insert holes 7 extending axially therethrough for inserting themolding material discharge pipe P therethrough.

The molding die D is assembled by inserting the first core C₁ of thefirst die part D₁ into the extrusion openings 5 and 6 of the second andthird die parts D₂ and D₃, inserting the second core C₂ of the seconddie part D₂ into the extrusion opening 6 of the third die part D₃ tothereby overlap the first, second and third die parts D₁, D₂ and D₃together, and thereafter inserting the molding material discharge pipe Pinto the pipe insert holes 7 of the second and third die parts D₂ andD₃.

As shown in FIG. 4, the molding material discharge pipe P is closed atone end thereof, and is formed with a radially-directed opening 8 in thepipe sidewall near the closed end.

Under the assembled condition of the molding die D as shown in FIGS. 1and 2, an annular extrusion passage 9 for extruding the molding materialto be molded into the body portion 2 of the hollow molding E is definedbetween the outer circumferential semicircular surfaces of the first andsecond cores C₁ and C₂ and the inner circumferential circular surface ofthe extrusion opening 6. Further, another extrusion passage 11 forextruding the molding material to be molded into the bridge 4 of thehollow molding E is defined between the spaced but flat opposed surfacesof the first and second cores C₁ and C₂.

When the closed end of the molding material discharge pipe P is engagedagainst the bottom of the recess 1 formed in the first die part D₁, thepipe P thus fully closes the supply passage V₁, as shown in FIGS. 1 and2. Thus, the molding material supplied through the passages V₂ and V₃ iscontinuously extruded from the extrusion passage 9, thereby molding theouter wall 2 of the hollow molding E. However, as the supply passage V₁is closed midway thereof by the discharge pipe P, the molding materialsupplied to the outer end of the supply passage V₁ enters the dischargepipe P through the opening 8 thereof, and is discharged through the openend of the discharge pipe P to the outside. As a result, a first hollowmolding part E₂ having no bridge 4 in the hollow portion 3 isextrusion-molded.

Thereafter, when the molding material discharge pipe P is moved axiallyto open the supply passage V₁ as shown in FIG. 3, the molding materialsupplied to and through the supply passage V₁ is continuously extrudedfrom the extrusion passage 11, thereby molding the bridge 4 of thehollow molding. As a result, a second hollow molding part E₂ having thebridge 4 in the hollow portion 3 is extrusion-molded. The moldinglengths of the first and second hollow molded parts E₁ and E₂ can bedefined by controlling a closed time and an open time of the supplypassage V₁ by the operation of the molding material discharge pipe P.

In this manner, by repeating the closing and the opening of the supplypassage V₁ of the first die part D₁ by the operation of the dischargepipe P with a predetermined time period, the first hollow molded part E₁having no bridge 4 in the hollow portion 3 and the second hollow moldedpart E₂ having the bridge 4 in the hollow portion 3 are continuouslyformed as shown in FIG. 8.

It is to be noted that the above description has been directed to theprinciple of the molding method according to the present invention. Inan actual molding operation, an extrusion molding is drawn by apredetermined tension. Accordingly, in order to avoid that the moldingis deformed by the tension because of a change in cross sectional areaof the molding, it is necessary to embed a core member such as a thinmetal sheet or a thread in the molding, or carry out two-color extrusionmolding using two kinds of molding materials having differenthardnesses, wherein the bridge is formed of the material having a smallhardness.

FIGS. 9 to 12 show a door seal S formed by utilizing the aboveprinciple. As shown in FIG. 10, a first door seal portion S₁ having nobridge is employed in an area where a door mirror 12 is located, whileas shown in FIG. 11, a second door seal portion S₂ having a plurality ofbridges 14 is employed in an area where a window glass 13 is located, sothat the second door seal portion S₂ is required to tightly contact thewindow glass 13 by a large seal reaction. Further, the first door sealportion S₁ is also employed at a corner area between a front sideportion and an upper side portion of the door seal S, so that the sealportion S₁ may be readily deformed with a reduced seal reaction.According to the molding method of the present invention, the first andsecond door seal portions S₁ and S₂ can be alternately and continuouslyformed to obtain the door seal S. Therefore, in comparison with theconventional molding method, the connection at the corner portionbetween the front side portion and the upper side portion of the doorseal S can be eliminated, and the bonding of the first seal portion S₁and the second seal portion S₂ in the straight front side portion of thedoor seal S can also be eliminated. As a result, the number ofmanufacturing steps can be largely reduced to thereby remarkably improvethe productivity.

Further, as shown in FIG. 12, five cores are required for the molding ofthe door seal S in this preferred embodiment.

According to the present invention, the first door seal portion havingno bridge in the hollow portion and the second door seal portion havingthe bridge in the hollow portion can be continuously molded.Accordingly, the connection between the first and second door sealportions are eliminated to thereby improve the appearance. Moreover, thecorner molding necessary in the conventional molding method can beeliminated to thereby largely reduce the number of manufacturing steps,resulting in remarkable improvement in the productivity.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. In a door seal for anautomobile, the improvement comprising a longitudinally elongateelastically deformable door seal member capable of being attached alongthe peripheral edge of a door opening of an automobile body, said sealmember having a first elongate hollow seal portion longitudinallycontinuous and integral with to a second elongate hollow seal portion,each said hollow seal portion being defined in cross section by anexterior peripheral wall which defines a hollow interior, said secondseal portion having an inner wall which is disposed within therespective hollow interior and bridges thereacross for connection tosaid exterior wall, said first seal portion being free of any innerwalls which bridge across the hollow interior thereof, and said firstand second elongate seal portions being integrally longitudinally formedby continuous molding for avoiding the presence of a joint therebetween.2. A door seal according to claim 1, wherein the exterior wall of eachof said first and second hollow seal portions defines a hollow tube, andwherein the inner wall as defined in said second seal portion projectsacross part of the hollow interior defined by the respective hollow tubefor connection to the exterior wall at two locations which arecircumferentially spaced around the exterior wall, said inner walldividing the hollow interior of said second seal portion into twolongitudinally extending interior spaces which are enclosed within saidexterior wall and are separate from one another by said inner wall.
 3. Adoor seal according to claim 2, wherein the door seal member is formedby extrusion molding and includes a core member extending longitudinallythereof and associated with and defining a part of the peripheral wall,the remainder of the peripheral wall and the inner wall being defined bya molding material of lesser hardness than the core member.